China Nonferrous Metallurgy

Rutile TiO? is the primary functional component in the coating of titanium electrode welding rods. At present， this material is mainly dependent on imports， with an external dependence rate exceeding 90%. In response to this situation， this study took low-grade titanium resources from Panxi region （with total content of MgO， SiO?， Al?O?， MnO and CaO higher than 10%） as raw materials. Combined with its material characteristics，the synthetic rutile-type TiO? was successfully prepared via the process of “titanium extraction by electric furnace smelting-fluidized strong oxidation roasting”. Thermodynamic analysis， phase characterization， microstructure observation and industrial tests were also carried out， and the main conclusions are as follows. The optimal process parameters were determined as fluidized roasting at 950℃ for 60 min. Under these conditions， the prepared product had a TiO ? content of 75. 2%， with the proportion of rutile-type TiO ? reaching 92%， sulfur content ≤ 0. 028% and carbon content ≤0. 008%. The slag fluidity was improved， and the weld porosity was reduced to 1. 2%， meeting the ultra-low sulfur and carbon requirements for welding consumable raw materials in high-end manufacturing. The mechanism of reconstructing rutile-type TiO? by oxidative roasting of low-grade titanium slag is identified as “solid solution decomposition-directional crystal growth-synergistic removal of impurities”. During roasting， associated impurities such as MgO and SiO? in the titanium concentrate are uniformly distributed at the nanoscale， forming “in-situ slag-forming components” and realizing synergistic resource utilization. This process realizes the efficient conversion of low-grade titanium concentrate into synthetic rutile for high-end welding materials. The TiO ? resource utilization rate reaches 85%，25 percentage points higher than that of traditional processes. The production cost per ton of synthetic rutile is about 2 538 RMB， In addition， the process features a short flow， no acidic wastewater discharge， and 40% CO? emission reduction， showing remarkable economic and environmental advantages. The research results break through the dependence of traditional synthetic rutile preparation processes on high-grade titanium raw materials， providing theoretical basis and technical support for the transformation of Panxi titanium resources from “resource-oriented” to “functional-oriented”